<?php
$db=new PDO('mysql:host=localhost','root','12qwas');
$r=$db->exec('create database if not exists db3');
var_dump($r);
$r=$db->exec('use db3');
var_dump($r);
$r=$db->exec('create table if not exists students(xh varchar(9) primary key, name varchar(50), age int default 0)');
var_dump($r);
$r=$db->exec("delete from  students where xh='233110205'");
var_dump($r);
$db->exec('truncate table students');
$r=$db->exec("insert into students(xh,name,age) values('233110265','李四',18),('233110205','王五',18),('233110255','张三',18)");
var_dump($r);
$r=$db->exec("update students set name='张三丰' where xh='233110205'");
var_dump($r);